In 1945 the USA dropped two nuclear bombs on Japan, at Nagasaki and Hiroshima. To date they are the only nuclear weapons to have been used in combat. Esri's map however shows that there have been many other nuclear detonations since the end of World War II. The nuclear detonations are shown on the as 'weapon development' or 'other'.

Some of the reasons given for the 'other' nuclear detonations seem a little dubious, I'm pretty certain most of these detonations were also used to help develop or test nuclear weapons.